(19)
(11) EP 0 379 984 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
06.02.1991 Bulletin 1991/06

(43) Date of publication A2:
01.08.1990 Bulletin 1990/31

(21) Application number: 90101063.7

(22) Date of filing: 19.01.1990
(51) International Patent Classification (IPC)5: H03F 3/343, H03K 17/615, H03F 1/32
(84) Designated Contracting States:
DE FR GB IT NL

(30) Priority: 26.01.1989 US 302502

(71) Applicant: NATIONAL SEMICONDUCTOR CORPORATION
Santa Clara California 95051-8090 (US)

(72) Inventor:
  • Wright, Michael E.
    Berkeley, CA 94709 (US)

(74) Representative: Sparing Röhl Henseler Patentanwälte 
Postfach 14 04 43
40074 Düsseldorf
40074 Düsseldorf (DE)


(56) References cited: : 
   
       


    (54) Feed forward Darlington circuit with reduced NPN reverse beta sensitivity


    (57) A Darlington output stage is shown in which the saturation voltage is reduced to the level of a single common emitter output transistor (13). The circuit includes a lateral feed-forward transistor (21) that bridges the driver transistor (14). A resistor (20) is included to ensure that the driver transistor (14) is turned off when the output transistor (13) saturates. An IC version of the circuit is set forth in detail.







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